Radio frequency identification (RFID) is a communication technology implementing a radio signal to identify a specific target and read/write related data. No physical or optical contact is needed between the specific target and a data reading system applying the RFID technology. As a result, data read/write speed of the data reading system is much faster than that of a traditional bar-code device.
An RFID tag is classified into active and passive types according to whether a chip is provided with an internal power supply. Taking a passive RFID tag as an example, an antenna of the RFID tag receives a radio signal transmitted from an RFID reader within a specific distance, and power needed by a chip circuit is provided by a received radio wave. Once started, the chip circuit of the RFID tag automatically decodes and interprets the signal received by the antenna, and provides information demanded by the RFID reader in the form of a radio signal, for example, an identification number of the tag, or an origin and a date of manufacture of goods to which the tag is attached.
Considering the RFID technology can be widely applied in fields of logistics management, public consumption, identification and smart homes and offices, the RFID reader integrated to portable electronics (such as mobile phones or PDAs) for improving convenience of various RFID applications has become an inevitable trend.
Nowadays as most portable electronics are faced with the restrictions of having low power consumption and low cost as well as being compact, further processes for combining more functions can be greater challenges. In other words, software and hardware resources of portable electronics are very limited and precious. As a result, how to combine RFID read/write functions under the condition of not occupying excessive software and hardware resources shall not be ignored.
However, RFID has a variety of standards and different specifications corresponding to different program codes; a general single-chip micro-processor is not likely to cover read/write functions of various RFID standards. An 8051 micro-processor, for example, is widely used and always applied as a core of an embedded system. Because an internal program memory is at most 64K bytes, an electronic product applying the 8051 micro-processor as an operation core of an RFID read/write module only holds a few kinds of RFID read/write program codes.
Therefore, holding various RFID read/write program codes in a single micro-processor is at the trade-off of applying a micro-processor with a larger memory capacity and a relatively higher price, or applying a plurality of micro-processors for different read/write standards, thereby greatly increasing cost of the electronic product.